simple python bundler

a.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""a"""


def a() -> None:
    print("this is a.py")

b.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""b"""


def b() -> None:
    print("this is b.py")

bundle.sh

#!/usr/bin/env bash

set -eu

echo 'bundling main.py main.bundle.py'

main() {
    cat <<EOF
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""bundled on $(date)"""

def __make_methods_static(cls):
    for name, method in cls.__dict__.items():
        if callable(method):
            setattr(cls, name, staticmethod(method))
    return cls
EOF

    while IFS= read -r line; do
        if echo "$line" | grep -iq 'cat:expand'; then
            mod="$(echo "$line" | awk '{print $2}')"
            printf '@__make_methods_static\nclass %s:\n' "$mod"
            sed 's/^/    /' "$mod.py"
        else
            echo "$line"
        fi
    done <main.py | sed '/^\s*$/d;s/\s\+$//'
}

main "$@" &>main.bundle.py

echo 'see main.bundle.py'

main.bundle.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""bundled on Mon 15 May 23:14:16 EEST 2023"""

def __make_methods_static(cls):
    for name, method in cls.__dict__.items():
        if callable(method):
            setattr(cls, name, staticmethod(method))
    return cls
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""main"""
from warnings import filterwarnings as filter_warnings
@__make_methods_static
class a:
    #!/usr/bin/env python3
    # -*- coding: utf-8 -*-
    """a"""
    def a() -> None:
        print("this is a.py")
@__make_methods_static
class b:
    #!/usr/bin/env python3
    # -*- coding: utf-8 -*-
    """b"""
    def b() -> None:
        print("this is b.py")
def main() -> int:
    """entry / main function"""
    print("main calling", a.a(), b.b())
    return 0
if __name__ == "__main__":
    assert main.__annotations__.get("return") is int, "main() should return an integer"
    filter_warnings("error", category=Warning)
    raise SystemExit(main())

main.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""main"""

from warnings import filterwarnings as filter_warnings

import a  # cat:expand
import b  # cat:expand


def main() -> int:
    """entry / main function"""

    print("main calling", a.a(), b.b())

    return 0


if __name__ == "__main__":
    assert main.__annotations__.get("return") is int, "main() should return an integer"

    filter_warnings("error", category=Warning)
    raise SystemExit(main())

u can remove empty line or extra whitespace removal, also its probably a nice idea to inherit from the module type :

from types import ModuleType
class ..(ModuleType): ...

u can modify they bundle script to do both of those